1. Field of the Invention
The present invention relates generally to photo-sensitive, light-activated switch apparatus responsive to ambient or other light conditions for turning ON and OFF electric devices, and more particularly to a switching device of a configuration suitable for location within a light socket and having an external light collector and flexible conduit for conducting light from the light collector to the switching device.
2. Brief Description of the Prior Art
There has long been a need for apparatus that can be used to turn conventional lighting fixtures ON and OFF as a function of ambient light conditions. For example, in the home environment various forms of such apparatus have been used exteriorly of the house to light porches, walks and driveways, and in the interior as a means to ward off potential unauthorized intruders during evening hours. The prior art has addressed this problem by providing bulky "piggy-back" light bulb receptacle devices for receiving a bulb and for carrying suitable daylight-responsive switching apparatus. The devices are adapted to screw into the light fixture socket with the bulb then being screwed into the device. However, such devices are not usable in some types of fixtures and are awkward to use in other types of fixtures.
U.S. Pat. No. 4,023,035 to Rodriquez discloses a device of the type described above, which includes a housing containing a light sensor and responsive switch apparatus to turn the light OFF and ON with ambient light conditions. The housing has a threaded portion for joining the lamp socket and an opposing socket to receive the bulb. The result is a significant displacement of the bulb position relative to the original lamp socket. This is a disadvantage because many lamp shade brackets and/or enclosures are not designed with enough clearance to accommodate the added length. Also, the location of the sensor inside the shade limits its effectiveness in detecting the ambient light. Furthermore, such apparatus is not available or even practical for use in the smaller candelabra style fixtures.
Pezzolo, U.S. Pat. No. 4,588,926 discloses a nightlight circuit which overcomes the flicker of previous automatic turn-on circuits using a photo-electric eye. Flicker is prevented by mounting a second photosensor in parallel with a portion of the voltage divider including the first electric eye to short out a portion of the voltage divider in response to the light turning on.
Other prior art U.S. Patents of general interest include Bernheim (U.S. Pat. No. 3,056,035), Bernheim (U.S. Pat. No. 3,163,768), Shepard (U.S. Pat. No. 3,341,711), Berlin (U.S. Pat. No. 3,538,379), and Pitel et al. (U.S. Pat. No. 4,568,826). These patents disclose related useful apparatus, but do not disclose or suggest a device that can be easily integrated into an existing lamp structure without significantly displacing the bulb.
As to other patented prior art, Ratner et al. (U.S. Pat. No. 4,988,921) discloses an apparatus including a sealed lamp (light bulb) assembly having a built-in photo sensitive switch. A disadvantage of this approach is the costly necessity of throwing away the photo switch when the bulb burns out.
Johnson in U.S. Pat. No. 5,030,890, although not disclosing an ambient light responsive unit, does disclose a means for gradually applying power to a bulb, implemented in a disc shaped apparatus that is installed in the lamp socket beneath the bulb. A disadvantage of the device is that it displaces the bulb to an extent requiring the use of an insulating ring to cover exposed bulb threads.
There thus still remains a need for a small, universally acceptable device that incorporates the various necessary features in a way that does not detract from the functional and/or aesthetic aspects of lamp fixtures in general.